<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			.transitionbox{
				width: 100px;
				height: 100px;
				background-color: black;
/*横向拉伸	transition: width 2s; */
			transition: height 2s;	
			}
/*鼠标移入div触发动画*/.transitionbox:hover{
		height: 300px;
}			
		</style>
	</head>
	<body>
		<h3>拉伸盒子动画效果</h3>
		<h5>traasition有两个参数，拉伸方向 动画执行时间</h5>
		
		<div class="transitionbox"></div>
	</body>
</html>
